Synthesis of composite of graphene and UO3 composite via one-step solution chemical reaction and its application to UO2-based accident tolerant fuel

In this paper, two kinds of composites constructed by UO₃ nanoflakes (which is UO₃·yNH₃·xH₂O, precisely) and different graphene oxide (GO) nanosheets (homemade GO, GO-h, and commercial GO, GO-c) were prepared via solution chemical reaction. The two kinds of GO share similar morphology and possess the same species of functional groups. Nevertheless, GO-h possesses higher oxidization degree and thus could adsorb more uranyl ions, and the corresponding composite shows a much more regular shape: UO₃ nanoflakes and GO nanosheets cross each other, which would help overcome the disadvantage of graphene aggregation. As a result, homemade reduced graphene oxide (RGO-h) sheets inside the final UO₂ pellets (named as UO₂/GO-h) could construct a well-bulit thermally conductive network to enhance its thermal conductivity. However, similar RGO-c network cannot be observed in the UO₂/GO-c pellest originated from GO-c. Therefore, only the thermal conductivity of UO₂/GO-h pellet acquires a dramatic increase, 37.30% relative to UO₂ pellet at 1200 °C, showing that UO₂/GO-h possesses great potential for the development of novel UO₂-based ATF fuels.